Design and Implementation Aspects of a novel Java P2P Simulator with GUI

Peer-to-peer networks consist of thousands or millions of nodes that might join and leave arbitrarily. The evaluation of new protocols in real environments is many times practically impossible, especially at design and testing stages. The purpose of this paper is to describe the implementation aspects of a new Java based P2P simulator that has been developed to support scalability in the evaluation of such P2P dynamic environments. Evolving the functionality presented by previous solutions, we provide a friendly graphical user interface through which the high-level theoretic researcher/designer of a P2P system can easily construct an overlay with the desirable number of nodes and evaluate its operations using a number of key distributions. Furthermore, the simulator has built-in ability to produce statistics about the distributed structure. Emphasis was given to the parametrical configuration of the simulator. As a result the developed tool can be utilized in the simulation and evaluation procedures of a variety of different protocols, with only few changes in the Java code.Comment: 8 Pages, 7 figures, This article was accepted for presentation in the IEEE Panhellenic Conference in Informatics (PCI 2008), http://www.aegean.gr/PCI200

The Right to Refuse to Deal, the Essential Facilities Doctrine, and the Digital Economy

Various commentators, as well as the 2020 report on competition in digital markets by the majority staff of the House Judiciary Committee, have advocated for the revival of the essential facilities doctrine, especially in the context of the digital economy. This Article examines the three phases in the development of the essential facilities doctrine and the right to refuse to deal—the foundations in the early twentieth century, the contraction of the right to refuse to deal and the expansion of the essential facilities doctrine in the mid-twentieth century, and the revival of the right to refuse to deal and the limiting of the essential facilities doctrine in the early twenty‑first century—and finds that there are considerable issues with the application of the doctrine to the digital economy even if the most expansionist precedents are applied. This Article also assesses the constitutionality of the essential facilities doctrine in general and its potential application to the digital economy in particular. In 1999, Abbott Lipsky and Gregory Sidak published the only article to examine at length potential constitutional issues with the essential facilities doctrine. Writing in the context of the Microsoft monopolization case, Lipsky and Sidak found the potential application of the essential facilities doctrine to Microsoft constitutionally suspect under the First and Fifth Amendments. Since the publication of that article, there have been major developments in essential facilities, refusal to deal, and First and Fifth Amendment jurisprudence. This Article examines issues with the potential application of the essential facilities doctrine to the digital economy based on recent First and Fifth Amendment decisions and finds it constitutionally suspect

The Right to Refuse to Deal, the Essential Facilities Doctrine, and the Digital Economy

Various commentators, as well as the 2020 report on competition in digital markets by the majority staff of the House Judiciary Committee, have advocated for the revival of the essential facilities doctrine, especially in the context of the digital economy. This Article examines the three phases in the development of the essential facilities doctrine and the right to refuse to deal—the foundations in the early twentieth century, the contraction of the right to refuse to deal and the expansion of the essential facilities doctrine in the mid-twentieth century, and the revival of the right to refuse to deal and the limiting of the essential facilities doctrine in the early twenty‑first century—and finds that there are considerable issues with the application of the doctrine to the digital economy even if the most expansionist precedents are applied. This Article also assesses the constitutionality of the essential facilities doctrine in general and its potential application to the digital economy in particular. In 1999, Abbott Lipsky and Gregory Sidak published the only article to examine at length potential constitutional issues with the essential facilities doctrine. Writing in the context of the Microsoft monopolization case, Lipsky and Sidak found the potential application of the essential facilities doctrine to Microsoft constitutionally suspect under the First and Fifth Amendments. Since the publication of that article, there have been major developments in essential facilities, refusal to deal, and First and Fifth Amendment jurisprudence. This Article examines issues with the potential application of the essential facilities doctrine to the digital economy based on recent First and Fifth Amendment decisions and finds it constitutionally suspect

Generating heat from conducting polypyrrole-coated PET fabrics

Heating effects in polypyrrole-coated polyethyleneterephthalate (PET)-Lycra&reg; fabrics were studied. Chemical synthesis was employed to coat the PET fabrics by polypyrrole using ferric chloride as oxidant and antraquinone- 2-sulfonic acid (AQSA) and naphthalene sulfonic acid (NSA) as dopants. The coated fabrics exhibited reasonable electrical stability, possessed high electrical conductivity, and were effective in heat generation. Surface resistance of polypyrrole-coated fabrics ranged from approximately 150 to 500 /square. Different connections between conductive fabrics and the power source were examined. When subjected to a constant voltage of 24 V, the current transmitted through the fabric decreased about 10% in 72 h. An increase in resistance of conductive fabrics subjected to constant voltage was observed<br /

Exploring electrical conductivity within mesoscopic phases of semi-conducting PEDOT:PSS films by Broadband Dielectric Spectroscopy

Poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonic acid (PEDOT:PSS), an optically transparent organic semi-conductor, constitutes a suspension of conducting PEDOT:PSS grains, shelled by an insulating layer of PSS. While a percolation network enhances dc conductivity, structural and electrical inhomogenity hinters electric charge flow giving rise to capacitance effects. In the present work, two distinct relaxation mechanisms are detected by Broadband Dielectric Spectroscopy (BDS). Double polarization mechamisms are predicted by bi-phase suspension dielectric theory. Within the frame of interfacial polarization, we propose a methodology to have an insight into the local conductivity of the interior of mesoscopic conducting phase.Comment: 6 figure

Metal to insulator transition in Conducting Polyaniline/Graphene Oxide composites

Broadband Dielectric Spectroscopy (BDS) measurements of P{\omicron}lyaniline/Graphene oxide composites were conducted for an as-prepared and a thermally annealed specimen, respectively, from 15K to room temperature. Electrical conductivity values of the annealed composite display a very modest rise denoting the important contributions of the GO component to achieving electrical stability of the polymer. Patterns of the dc conductivity as a function of temperature also reveal a metal to insulator transition around 75K. The transition is dominated by two key factors; temperature and annealing process. Metal-like and insulating features are subsequently detected, as well, and accordingly described to provide a qualitative inspection of the charge transfer mechanisms involvedComment: Applied Physics Letters (accepted

Long aging time thermal degradation of the ac conductivity and complex permittivity of conducting polypyrrole

The modification of the ac conductivity and the complex permittivity of conducting polypyrrole was monitored throughout a two years thermal aging at 343K. Reduction of the cross-over frequency is correlated with the degradation of dc-conductivity, while the ac conductivity region corresponding to the so-called 'universal' dielectric relaxation remains practically invariant during the first year of ageing, which implies a collective co-operativity among multiple degradation processes that yield a practically time-independent effective disordered environment. A broad dielectric loss peak recorded in fresh specimens splits into two distinct relaxations for intermediate stages of the annealing process. The ageing-time evolution of the dc component and the relaxations are qualitatively analysed and time constants are determined.Comment: Synth. metals (2011) in prin

Anisotropic Curie temperature materials

Existence of anisotropic Curie temperature materials [E. R. Callen, Phys. Rev. 124, 1373 (1961)] is a longstanding prediction - materials that become paramagnetic along certain crystal directions at a lower temperature while remaining magnetically ordered in other directions up to a higher temperature. Validating Callen's theory, we show that all directions within the basal plane of monoclinic Fe7S8 single crystals remain ordered up to 603 K while the hard c-axis becomes paramagnetic at 225 K. Materials with such a large directional dependence of Curie temperature opens the possibility of uniquely new devices and phenomena